Cannabis, cognition, and the role of nicotine with Emese KroonCannabis, cognition, and the role of nicotine with Emese Kroon
Addiction Audio
Dr Emese Kroon discusses how heavy cannabis use, often combined with nicotine, relates to cognitive functioning such as memory, attention and IQ. The conversation highlights surprising research findings and considers how these results may inform harm reduction and clinical understanding of cannabis use disorder.
20:21•4 Sept 2026
Cannabis, Cognition and Nicotine: What the Research Really Shows
Episode Overview
- Many cannabis users mix tobacco into joints and may not realise they are regular nicotine users, despite nicotine having its own cognitive effects.
- Cannabis use disorder is linked with poorer interference control, memory (immediate and delayed), executive functions and estimated IQ compared with non-using controls.
- Within a group of very heavy cannabis users, cognitive performance did not clearly worsen with higher levels of use, suggesting possible ceiling effects from near-daily consumption.
- Nicotine showed a limited role, but it altered the relationship between cannabis use disorder symptoms and working memory in non-co-users compared with co-users.
- Cognitive studies can support harm reduction by helping people understand how reducing cannabis use might improve everyday memory, attention and functioning.
“They often do not recognise that if they put tobacco in with their cannabis, that they are actually also nicotine users.”
Understand the complexities of addiction with insights from a researcher who spends her days measuring how drugs affect thinking. This conversation focuses on cannabis, cognition, and the often-overlooked part nicotine plays in the mix. Postdoctoral researcher Dr Emese Kroon talks with Dr Tsen Vei Lim about her study of people with cannabis use disorder who were using cannabis almost daily, often more than a gram a day.
Crucially, many of them also used tobacco, frequently mixing it with cannabis in joints. As Emese puts it, “they often do not recognise that if they put tobacco in with their cannabis, that they are actually also nicotine users”, even though nicotine is affecting their brain at the same time.
You’ll hear a clear rundown of what’s known about cannabis and the brain: consistent links with problems in episodic memory, learning, attention and reaction time, and less consistent findings for more complex skills like decision-making. Emese explains that heavy use can lead to ongoing difficulties, but some functions may recover with sustained abstinence. The study’s results are surprising in places.
Compared with control participants, people with cannabis use disorder showed poorer performance on interference control (via a Stroop task), immediate and delayed recall, executive functions and estimated IQ. Yet within the heavy-use group, these deficits didn’t neatly increase with heavier use, suggesting a possible “ceiling effect” from near-daily consumption.
Nicotine’s role turned out to be smaller than expected, with one notable pattern: nicotine seemed to change the link between cannabis symptoms and working memory, hinting at a complex interaction rather than a simple good-or-bad effect. This episode is aimed at researchers, clinicians, students and anyone curious about how cannabis might be affecting their thinking, framing cognitive research as a bridge between lab findings and people’s day-to-day struggles with memory, attention and control.
It might leave you asking: if cannabis use changed your thinking, how much would that matter to you?
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